Receiving system for high-frequency electrical oscillations



Patented Mar.`l 15,1927. l .l UmransrA'res. PATENT ersten..

Lamm n. recrean-Namco. round, @ewes/amener, marmeren encontrarme.

` nncmrvm SYSTEM, non. HIGHFFREQUENGY ELECTRICAL osornrae'noars.. application ined January 1c, umJ sentano; caress;-

While our invention. relates generally to sistancei R', andthe tunedcouplingscompris.- systemsfor receiving. highg frequency electriing inductance variable condenser calloscillations, has for a particular objectthe C, in the: plate cr'cui-tof the liaststagei of= employment ofa' plurality of tuned kreceivers radio frequencyV-v amplification and indue- 60 5 with asingle collector ofthe high frequencyl tance L, variable condenser C, in, the oscillations. Y I v Y grid; circuit of the detecting vacuum tube.

JL vfur-ther object is-the reception ofv a plulnductance L2. in the. `plate circuit of. the4 'rality of communications at dierent fredetecting. vacuum tube coupled to the inducquiencies, and providing means to prevent tance L3 inthe grid circuitl provides` for adl- 65 the tuning operations of the receivers from ditionalafmplifi'cation of the signal throughs interfering one vwith the other through adre-generation, or for producingl oscillations justment of thetuning elementsv for reception of sustained wave signals.l by

Gun invention; isof particular' value for the autodyne method of; obtaining beats. instance in receiving radio, signals in loca- The resista-nce R6 and shuntedcapacityi C, 70

tiene whzere.-Y there are limitations restricting form the well known grid-leak stopping? thenamber-offantennzc which can be erected condenser combination in circuit arran e'- Y, though itmay be desired; to receive' a large ments of this kind. Battery B5, provi es number'- of signals, whichr condition may be for heating currents for the filaments of the encountered-onboard ships, in hotels or in vacuum tubes,v the amount ot heatingcurrent 75 apartmenthousest- With our systemasingles for vacuum tube VT, and VTI being con# antennacan be erected on the roof of a trolled through rheostat R2 end forvacaum buldingynumerousbranchi circuits from this tube V T1. through rheostatt R2, 4'Battery colecting antenna lead; tothe various rooms Bs supplies the plate circu-itenergyfor these off thebuilding,l and receiving.' systems con# vacuum tubesiA T is a. telephone on other' 80 nectedtofthese brarnchcifrcuits can bei operresponsive device shunted by the radio freated at the will of theA occupantsof one quency by-pass condenser (32,. room without interference to the operation B2. is a second branch circuit in.I series withof siflarfsyems locatedin the other rooms the collectingl antenmly A, but in par-allelf` of the buildilztegy with branclrci-rcuit B1, eontainingresistance 85 Our invention will be best understood by R2, switch S2, resistance R2', tunable circuit reference to the figure of the drawing which containing inductancc L2 and variable ca. illustrates the invention used in connection pacity G2, all substantially of the same arwith the receptiony of radio signals. rangement and values as described in con- A is an antenna collector of conventional nection with branch circuit Bl. A receiver 90 form grounded at G. B1 is a branch circuit is also connected to this branch circuit in in series with the antenna Acontaining a shunt with the switch S2, and through a high resistance R1, preferably of the order variable contactor V2 to resistance R2, the of 50,000 ohms. In series with the resistance receiver having 'a radio frequency amplifier R1L is the double-pole double-throw switch of which the vacuum tube V'I2 is the rst 95 40 S1. To one pair of terminals of this switch stage, all substantially as described in conthere is connected a high resistance R1', nection with branch circuit B1. i' preferably of the order of one half a Any number of branch circuits as B3 and megohm, and to the other pair of terminals B4 indicated by arrows may be added to the there is connected a tunable circuit containsystem to include elements substantially as 100 2,

ing inductance LJL and variable capacity C2. heretofore described.

In shunt to the switch S1 wev connect a re` The operation of the system is as follows:

ceiver, one connection being made through It it is desired to receive a signal at a a variable contactor V1, the contact being given frequency on anyone of the branch variable over the extent of the resistance R1. circuits such as B1, the switch S1 is thrown 105 5 The receiver illustrated includes a radio freto the right to include the resistance R1 in quency amplier in two steps containing series with the resistance R1. The variable the three-electrode vacuum tubes VT1 and contacter V1 is preferably moved to the top f VT2 interlinked through the radio freof the resistance R1 to include all of this quency transformer RF. The output of the resistance between the grld and .filaments no f radio frequency amplifier' is delivered to a leads to the vacuum tube VTl. :Th1s ad]ust v vacuum tube rectifier VT2 through a rement we term the hunting position. The

condensers C5 and C are then adjusted until the desired signal is best heard, then leaving these condensers at the adjusted setting the switch Sl is thrown to the left to include the tunable circuit containing inductance L1 and variable capacity C1 in series with the resistance R1, and the variable condenser C, adjusted until maximum intensity of signal is obtained. Improved selectivity may be obtained by moving the variable contacter V1 to the lower part of the resistance R1, leaving the vacuum tube VT1 in shunt with the tunable circuit only.

Any number of the receivers connected to the branch circuits may be put into operation in the same manner, and we have found that with the system substantially as illustrated the carrying out of the adjustments for the independent receivers does not interfere with the adjustment of other receivers which may be in operation.

We have found that delivering the output of the radio frequency amplifier to its coupled detector circuit through resistance R5, of approximately 5000 ohms, improves the selectivity of the system.

The non-interfering properties of the sys tem can undoubtedly be ascribed to the aperiodic condition in which the ant-enna is always maintained by the comparatively high resistances R1, R2 etc. in the branch circuits. These resistances do not materially decrease the receiving efhciency of the system, for even though their resistances are high yet the impedances of the tunable circuits in series therewith are materially greate er for signals of the desired frequency. At

the same time these resistances keep signals of undesired frequencies out of the branch circuits to a considerable extent, and those parts of the signal which do enter encounter low impedances in the tunable circuits to which the undesired frequencies are not in resonance, and therefore transfer low values of potential to the shunted receivers.

Having described our invention we claim:

l. In a system for receiving high frequency oscillations the combination of a collector for said oscillations, a plurality of branch circuits connected in series with said collector and in parallel with each other, each branch circuit containing a high resistance and a parallel tunable circuit in series with said resistance, and a receiver connected to each of said branch circuits in a position in shunt with said parallel tunable circuits and any selected portion of said high resistances.

2. In a system for receiving high frequency oscillations the combination of a collector for said oscillations, a plurality of branch circuits connected in series with said collector and in parallel with each other, each branch containing a high resistance and having a parallel tunable circuit and a resistance substantially higher than said first resistance together with means for alternately connecting it in series with said first resistance, and receivers operated by the difference of lected oscillations at the terminals of the connections for said parallel tunable circuit and second high resistance.

ALBERT H. TAYLOR. LEo o. YOUNG.

potentials created by the colf' 

